Greywater Recycling

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Greywater is usually defined as used water from basins, baths and showers. Sometimes the definition includes water from the kitchen sink, dishwasher and washing machine but water from these sources contains much higher levels of bacteria, grease and solids.

Greywater can usually be treated with membrane filters, in which case it will avoid use of expensive rotating mechanical equipment. The filtered and treated water can then be used for toilet flushing and irrigation purposes.

Ideal buildings for greywater recycling are hotels, student accommodation or high rise structures with living accommodation.  These buildings provide high system efficiency as the bath and shower water provides a constant supply that is reused for WC flushing, often the system efficiency will be higher than a rainwater only system.  Private homes can have greywater recycling but a basement room is preferred for the greywater plant location, external buried greywater tanks are prohibitively expensive.  Combined rain and greywater systems are possible but the added efficiency from the rainwater depends on the building use.

Ecozi use membrane filtration technology from Germany to remove particles to 5 microns.  This removes 99% of the bacteria, the water is then available for WC and some irrigation applications.  The water is aerated and processed through three storage cisterns.  When designing or specifying a greywater system pay particular attention to the filtration, stored water environment and maintenance. Low price systems will have poor filtration that leads to lower water quality and reliability issues.  Ecozi systems are designed for 12 month maintenance intervals and use aeration pumps to help maintain water quality.

Storage cisterns can be located in basement plant rooms or buried but simpler maintenance and lower cost installation is achieved from basement located storage and plant. Ecozi can provide full design and installation services.

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